Method for preventing, treating and diagnosing disorders of protein aggregation

ABSTRACT

Disclosed are methods of preventing, treating, or diagnosing in a subject a disorder in protein folding or aggregation, or amyloid formation, deposition, accumulation, or persistence consisting of administering to said subject a pharmaceutically effective amount of inositol stereoisomers, enantiomers or derivatives thereof.

RELATED APPLICATIONS

This application is a national stage filing of correspondinginternational application number PCT/CA2004/000272, filed Feb. 27, 2004,which claims priority to U.S. patent application Ser. No. 10/787,621,filed Feb. 26, 2004, which claims benefit of U.S. ProvisionalApplication Nos. 60/451,363, 60/520,958 and 60/523,534, filed Feb. 27,2003, Nov. 17, 2003 and Nov. 19, 2003, respectively, all of which arehereby incorporated by reference.

FIELD OF THE INVENTION

The invention relates to methods for treating Alzheimer's Disease andother amyloidoses; more particularly, it relates to methods forinhibiting and reducing amyloid fibril formation in therapeuticintervention in Alzheimer's disease and other amyloidoses.

DESCRIPTION OF THE RELATED ART

Alzheimer's disease is characterized neuropathologically by amyloiddeposits, neurofibrillary tangles, and selective neuronal loss. Themajor component of the amyloid deposits is amyloid-β(Aβ), a 39-43residue peptide. Soluble forms of Aβ generated from cleavage of amyloidprecursor protein are normal products of metabolism. The importance ofresidues 1-42 (Aβ42) in Alzheimer's disease was highlighted in thediscovery that mutations in codon 717 of the amyloid precursor proteingene, presenilin 1 and presenilin 2 genes result in an increasedproduction of Aβ42 over Aβ1-40. These results in conjunction with thepresence of Aβ 42 in both mature plaques and diffuse amyloid lead to thehypothesis that this more amyloidogenic species may be the criticalelement in plaque formation. This hypothesis was supported by the factthat Aβ42 deposition precedes that of Aβ40 in Down's syndrome in PS1mutations and in hereditary cerebral hemorrhage with amyloidosis.

Many in vitro studies have demonstrated that Aβ can be neurotoxic orenhance the susceptibility of neurons to excitotoxic, metabolic, oroxidative insults. Initially it was thought that only the fibrillar formof A was toxic to neurons but more thorough characterization of Aβstructures demonstrated that dimers and small aggregates of Aβ are alsoneurotoxic. These data suggested that prevention of Aβ oligomerizationwould be a likely strategy to prevent AD-related neurodegeneration.Several studies have demonstrated that in vitro Aβ-induced neurotoxicitycan be ablated by compounds that can increase neuronal resistance bytargeting cellular pathways involved in apoptosis, block downstreampathways after Aβ induction of destructive routes, or block Aβoligomerization and ultimately fibril formation. The site at which Aβacts to induce neurotoxicity has yet to be elucidated but its toxiceffects have been blocked by a variety of disparate agents.

Docking of Aβ-fibrils to neuronal and glial cell membranes may be anearly and intervenable step during the progression of AD. Formation ofamyloid plaques, as well as neurotoxicity and inflammation may be director indirect consequences of the interaction of A with moleculescontaining sugar moieties. Previous studies have demonstrated that Aβinteraction with glycosaminoglycans results in aggregation of Aβpossibly adding to their insolubility and plaque persistence.Glycosaminoglycans have also been implicated in neuronal toxicity andmicroglial activation. Alternatively, interaction with glycolipids suchas gangliosides results in the stabilization and prevention of Ab fibrilformation, as well as, the site of Aβ production. The family ofphosphatidylinositols, on the other hand, results in acceleration offibril formation. The headgroup of phosphatidylinositol is myo-inositol,a naturally occurring simple sugar involved in lipid biosynthesis,signal transduction, and osmolarity control.

It is also noteworthy that a variety of other human diseases alsodemonstrate amyloid deposition and usually involve systemic organs (i.e.organs or tissues lying outside the central nervous system), with theamyloid accumulation leading to organ dysfunction or failure. InAlzheimer's disease and “systemic” amyloid diseases, there is currentlyno cure or effective treatment, and the patient usually dies within 3 to10 years from disease onset.

U.S. Pat. No. 4,847,082 discloses the use of phytic acid, a phytatesalt, an isomer or hydrolysate of phytic acid for the treatment ofAlzheimer's disease. It also discloses that isomers of phytic acid orphytate salt comprise the hexakisphosphate myo-inositol,hexakisphosphate scyllo-inositol, hexakisphosphate D-chiro-inositol,hexakisphosphate L-chiro-inositol, hexakisphosphate neo-inositol andhexakispbosphate muco-inositol conformations. Phytic acid isinositol-hexakisphosphate (IP6).

U.S. Pat. No. 5,112,814 discloses the use of phytic acid and isomersthereof for the treatment of Parkinson's disease. As is the case withU.S. Pat. No. 4,847,082, the phytic acid isomers disclosed in thispatent retain the six phosphate groups on the six-carbon inositol sugar.

It is noteworthy that in subsequent publications, the ability ofinositol-monophosphate, inositol-1,4-bisphosphate andinositol-1,4,5-triphosphate to inhibit amyloid-beta peptidefibrillogenesis were investigated and found not to be effective (J. Mol.Biol. 278:183-194, 1998).

Barak et al. disclose the use of inositol for the treatment ofAlzheimer's Disease (AD). (Prog Neuro-psychoparmacol & Biol Psychiat.20:729-735, 2000). However, this reference does not disclose the use ofinositol isomers. Patients treated with inositol did not show anysignificant differences in overall cognitive function scores (CAMCOGindex) between inositol and placebo (dextrose) in AD patients while twospecific subscales of the CAMCOG index did show significant improvement(orientation and language).

Levine J. reviews the above Barak et al. paper and specifically statesthat inositol treatment is not beneficial in AD or ECT-induced cognitiveimpairment (Eur Neuropsychoparm. 1997; 7,147-155, 1997).

Colodny L, et al. suggests further studies for the usefulness ofinositol in Alzheimer's disease by referring to the above Barak et al.paper and therefore does not disclose or suggest such use for inositolisomers (Altern Med Rev 3(6):432-47, 1998).

McLaurin et al. disclosed that myo-inositol stabilizes a small micelleof Aβ42 (J. Mol. Biol. 278, 183-194, 1998). In addition, McLaurin et al.disclose that epi- and scyllo- but not chiro-inositol were able toinduce a structural transition from random to β-structure in Aβ42 (JBiol. Chem. June 16; 275(24):18495-502, 2000; and J Struct Biol130:259-270, 2000). Alternatively, none of the stereoisomers were ableto induce a structural transition in Aβ40. Electron microscopy showedthat inositol stabilizes small aggregates of Aβ42. These references alsodisclose that inositol-Aβ interactions result in a complex that isnon-toxic to nerve growth factor-differentiated PC-12 cells and primaryhuman neuronal cultures.

Much work in Alzheimer's disease has been accomplished, but little isconventionally known about compounds or agents for therapeutic regimesto arrest or reverse amyloid formation, deposition, accumulation and/orpersistence that occurs in Alzheimer's disease and other amyloidoses.

New compounds or agents for therapeutic regimes to arrest or reverseamyloid formation, deposition, accumulation and/or persistence thatoccurs in Alzheimer's disease and other amyloidoses are thereforedesperately needed.

SUMMARY OF THE INVENTION

The present invention provides a method of treating or preventing in asubject a condition of the central or peripheral nervous system orsystemic organ associated with a disorder in protein folding oraggregation, or amyloid formation, deposition, accumulation, orpersistence comprising administering to said subject a pharmaceuticallyeffective amount of compound selected having the following structure:

wherein each of R₁, R_(1′), R₂, R_(2′), R₃, R_(3′), R₄, R_(4′), R₅,R_(5′), R₆, and R_(6′) is independently selected from the group of:

-   -   (a) hydrogen atom;    -   (b) NHR₇, wherein said R₇ is selected from the group of        hydrogen; C₂-C₁₀ acyl and C₁-C₁₀ alkyl;    -   (c) NR₈R₉, wherein said R₈ is C₂-C₁₀ acyl or C₁-C₁₀ alkyl and        said R₉ is C₂-C₁₀ acyl or C₁-C₁₀ alkyl;    -   (d) OR₁₀, wherein said R₁₀ is selected from the group of no        group, hydrogen, C₂-C₁₀ acyl, C₁-C₁₀ alkyl and SO₃H;    -   (e) C₅-C₇ glycosyl;    -   (f) C₃-C₈ cycloalkyl optionally substituted with a substituent        selected from the group of hydrogen, OH, NH₂, SH, OSO₃H and        OPO₃H₂;    -   (g) SR₁₁, wherein R₁₁ is selected from the group of hydrogen,        C₁-C₁₀ alkyl and O₃H;    -   (h) C₁-C₁₀ alkyl optionally substituted with a substituent        selected from the group of hydrogen, OR₁₀, NHR₇, NR₈R₉ and SR₁₁;        and    -   (i) C₃-C₈ cycloalkyl optionally substituted with a substituent        selected from the group of hydrogen, OR₁₀, NHR₇, NR₈R₉ and SR₁₁,        providing that the compound is not myo-inositol.

The present invention also provides a method of preventing abnormalprotein folding, abnormal protein aggregation, amyloid formation,deposition, accumulation, or persistence, or amyloid lipid interactionsin a subject comprising administering to said subject a pharmaceuticallyeffective amount of a compound having the following structure:

wherein each of R₁, R_(1′), R₂, R_(2′), R₃, R_(3′), R₄, R_(4′), R₅,R_(5′), R₆, and R_(6′) is independently selected from the group of:

-   -   (a) hydrogen atom;    -   (b) NHR₇, wherein said R₇ is selected from the group of        hydrogen; C₂-C₁₀ acyl and C₁-C₁₀ alkyl;    -   (c) NR₈R₉, wherein said R₈ is C₂-C₁₀ acyl or C₁-C₁₀ alkyl and        said R₉ is C₂-C₁₀ acyl or C₁-C₁₀ alkyl;    -   (d) OR₁₀, wherein said R₁₀ is selected from the group of no        group, hydrogen, C₂-C₁₀ acyl, C₁-C₁₀ alkyl and SO₃H;    -   (e) C₅-C₇ glycosyl;    -   (f) C₃-C₈ cycloalkyl optionally substituted with a substituent        selected from the group of hydrogen, OH, NH₂, SH, OSO₃H and        OPO₃H₂;    -   (g) SR₁₁, wherein R₁₁ is selected from the group of hydrogen,        C₁-C₁₀ alkyl and O₃H;    -   (h) C₁-C₁₀ alkyl optionally substituted with a substituent        selected from the group of hydrogen, OR₁₀, NHR₇, NR₈R₉ and SR₁₁;        and    -   (i) C₃-C₈ cycloalkyl optionally substituted with a substituent        selected from the group of hydrogen, OR₁₀, NHR₇, NR₈R₉ and SR₁₁,        providing that the compound is not myo-inositol.

The present invention further provides a method of causing thedissociation of abnormally aggregated proteins and/or dissolving ordisrupting pre-formed or pre-deposited amyloid fibril or amyloid in asubject comprising administering to said subject a pharmaceuticallyeffective amount of a compound having the following structure:

wherein each of R₁, R_(1′), R₂, R_(2′), R₃, R_(3′), R₄, R_(4′), R₅,R_(5′), R₆, and R_(6′) is independently selected from the group of:

-   -   (a) hydrogen atom;    -   (b) NHR₇, wherein said R₇ is selected from the group of        hydrogen; C₂-C₁₀ acyl and C₁-C₁₀ alkyl;    -   (c) NR₈R₉, wherein said R₈ is C₂-C₁₀ acyl or C₁-C₁₀ alkyl and        said R₉ is C₂-C₁₀ acyl or C₁-C₁₀ alkyl;    -   (d) OR₁₀, wherein said R₁₀ is selected from the group of no        group, hydrogen, C₂-C₁₀ acyl, C₁-C₁₀ alkyl and SO₃H;    -   (e) C₅-C₇ glycosyl;    -   (f) C₃-C₈ cycloalkyl optionally substituted with a substituent        selected from the group of hydrogen, OH, NH₂, SH, OSO₃H and        OPO₃H₂;    -   (g) SR₁₁, wherein R₁₁ is selected from the group of hydrogen,        C₁-C₁₀ alkyl and O₃H;    -   (h) C₁-C₁₀ alkyl optionally substituted with a substituent        selected from the group of hydrogen, OR₁₀, NHR₇, NR₈R₉ and SR₁₁;        and    -   (i) C₃-C₈ cycloalkyl optionally substituted with a substituent        selected from the group of hydrogen, OR₁₀, NHR₇, NR₈R₉ and SR₁₁,        providing that the compound is not myo-inositol.

The present invention also provides a method of diagnosing the presenceof abnormally folded or aggregated protein and/or amyloid fibril oramyloid in a subject comprising: (a) administering to said subject aradioactive compound or compound tagged with a substance that emits adetectable signal in a quantity sufficient and under conditions to allowfor the binding of said compound to the abnormally folded or aggregatedprotein and/or fibrils or amyloid, if present; and (b) detecting theradioactivity or the signal from the compound bound to the abnormallyfolded or aggregated protein and/or fibrils or amyloid, thus diagnosingthe presence of abnormally folded or aggregated protein and/or amyloidfibril or amyloid in said subject, wherein said compound has thefollowing structure:

wherein each of R₁, R_(1′), R₂, R_(2′), R₃, R_(3′), R₄, R_(4′), R₅,R_(5′), R₆, and R_(6′) is independently selected from the group of:

-   -   (a) hydrogen atom;    -   (b) NHR₇, wherein said R₇ is selected from the group of        hydrogen; C₂-C₁₀ acyl and C₁-C₁₀ alkyl;    -   (c) NR₈R₉, wherein said R₈ is C₂-C₁₀ acyl or C₁-C₁₀ alkyl and        said R₉ is C₂-C₁₀ acyl or C₁-C₁₀ alkyl;    -   (d) OR₁₀, wherein said R₁₀ is selected from the group of no        group, hydrogen, C₂-C₁₀ acyl, C₁-C₁₀ alkyl and SO₃H;    -   (e) C₅-C₇ glycosyl;    -   (f) C₃-C₈ cycloalkyl optionally substituted with a substituent        selected from the group of hydrogen, OH, NH₂, SH, OSO₃H and        OPO₃H₂;    -   (g) SR₁₁, wherein R₁₁ is selected from the group of hydrogen,        C₁-C₁₀ alkyl and O₃H;    -   (h) C₁-C₁₀ alkyl optionally substituted with a substituent        selected from the group of hydrogen, OR₁₀, NHR₇, NR₈R₉ and SR₁₁;        and    -   (i) C₃-C₈ cycloalkyl optionally substituted with a substituent        selected from the group of hydrogen, OR₁₀, NHR₇, NR₈R₉ and SR₁₁,        providing that the compound is not myo-inositol.

The present invention further provides a method of diagnosing thepresence of abnormally folded or aggregated protein and/or amyloidfibril or amyloid in a subject comprising: (a) collecting a sample fromsaid subject; (b) contacting said sample with a radioactive compound orcompound tagged with a substance that emits a detectable signal underconditions to allow the binding of said compound to the abnormallyfolded or aggregated protein and/or amyloid fibril or amyloid ifpresent; and (c) detecting the radioactivity or the signal from thecompound bound to the abnormally folded or aggregated protein and/orfibrils or amyloid, thus diagnosing the presence of abnormally folded oraggregated protein and/or amyloid fibril or amyloid in said subject,wherein said compound has the following structure:

wherein each of R₁, R_(1′), R₂, R_(2′), R₃, R_(3′), R₄, R_(4′), R₅,R_(5′), R₆, and R_(6′) is independently selected from the group of;

-   -   (a) hydrogen atom;    -   (b) NHR₇, wherein said R₇ is selected from the group of        hydrogen; C₂-C₁₀ acyl and C₁-C₁₀ alkyl;    -   (c) NR₈R₉, wherein said R₈ is C₂-C₁₀ acyl or C₁-C₁₀ alkyl and        said R₉ is C₂-C₁₀ acyl or C₁-C₁₀ alkyl;    -   (d) OR₁₀, wherein said R₁₀ is selected from the group of no        group, hydrogen, C₂-C₁₀ acyl, C₁-C₁₀ alkyl and SO₃H;    -   (e) C₅-C₇ glycosyl;    -   (f) C₃-C₈ cycloalkyl optionally substituted with a substituent        selected from the group of hydrogen, OH, NH₂, SH, OSO₃H and        OPO₃H₂;    -   (g) SR₁₁, wherein R₁₁ is selected from the group of hydrogen,        C₁-C₁₀ alkyl and O₃H;    -   (h) C₁-C₁₀ alkyl optionally substituted with a substituent        selected from the group of hydrogen, OR₁₀, NHR₇, NR₈R₉ and SR₁₁;        and    -   (i) C₃-C₈ cycloalkyl optionally substituted with a substituent        selected from the group of hydrogen, OR₁₀, NHR₇, NR₈R₉ and SR₁₁,        providing that the compound is not myo-inositol.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows the structure of myo-, epi- and scyllo-inositol whileFIGS. 1B-1H show the spatial reference memory version of the Morriswater maze test in TgCRND8 mice. Myo-inositol treatment did not altercognitive function (1B). At 6 months of age, non-treated TgCRND8 (n=10)show cognitive impairment relative to non-Tg controls and epi- (1C) andscyllo-inositol (1D) treated mice (n=10 per group, p<0.02 untreated vstreated). The performance of epi-inositol treated TgCRND8 mice remainedimpaired with respect to non-Tg littermates (1E) whereas the performanceof scyllo-inositol TgCRND8 approached that of non-Tg littermates (1F).Non-Tg littermate behavior was not effected by either epi- (1G) orscyllo-inositol (1H) treatment. Vertical bars represent S.E.M.

FIGS. 2A-2I show at 6 months of age, the plaque burden and astrogliosisin TgCRND8 treated with epi- and scyllo-inositol treated mice. Controlanimals have a high plaque load and astrogliosis in the hippocampus (2A)and cerebral cortex (2B). Higher magnification demonstrates thatastrocytic activation is not only associated with plaque load (2C).Epi-inositol treatment has a modest effect on amyloid burden with adecrease in astrogliosis (2D, 2E and 2F). Scyllo-inositol treatmentsignificantly decreased amyloid burden and gliosis (2G, 2H, and 2I).Higher magnification illustrates the smaller mean plaque size inscyllo-inositol treated mice (2I). Astrocytes were labeled usinganti-GFAP antibody and plaque burden was identified using anti-Aβantibody. Scale Bar 450 microns (A,B,D,E,G,H) and 94 microns (C,F,I).

FIGS. 3A-3D show that the Aβ species, 1-42, 1-40 and 1-38, in controland treated TgCRND8 mice was indistinguishable (3A) as was the extent ofAPP processing (3B). Vascular amyloid burden was quantitated on serialsagittal sections in treated and untreated TgCRND8 mice. TgCRND8 micehave a significant vascular amyloid burden that is associated with smalland medium sized vessels, the load is decreased in scyllo-inositoltreated TgCRND8 mice (3A). Scyllo-inositol treatment significantlydecreased the total vascular load in comparison to untreated andepi-inositol treated TgCRND8 mice (3C). Scyllo-inositol decreases plaquedeposition as illustrated by the significant decrease in mean plaquesize (3D).

FIG. 4 shows the effect of water on the cognitive function of TgCRND8and non-Tg mice using the spatial reference memory version of the MorrisWater Maze in a three day trial paradigm.

FIG. 5 shows the effect of scyllo-inositol on the cognitive function ofTgCRND8 and non-Tg mice using the spatial reference memory version ofthe Morris Water Maze in a three day trial paradigm.

FIG. 6 shows the effect of epi-inositol on the cognitive function ofTgCRND8 and non-Tg mice using the spatial reference memory version ofthe Morris Water Maze in a three day trial paradigm.

FIG. 7 shows the effect of myo-inositol on the cognitive function ofTgCRND8 and non-Tg mice using the spatial reference memory version ofthe Morris Water Maze in a three day trial paradigm.

FIG. 8 shows the effect of scyllo-inositol, epi-inositol andmyo-inositol on the cognitive function of TgCRND8 (learning phase andmemory test) and compared with wild type mice using the spatialreference memory version of the Morris Water Maze in a three-day trialparadigm.

FIG. 9 shows the percentage of brain area covered with plaques inuntreated TgCRND8 mice versus mice treated with scyllo-inositol,epi-inositol or myo-inositol.

FIGS. 10A and 10B show the survival rates of TgCRND8 mice treated withwater versus epi-inositol or myo-inositol (10A) or versusscyllo-inositol (10B).

FIGS. 11 A-D show the results of spatial reference memory version of theMorris Water Maze test in 6-month old TgCRND8 mice non-treated ortreated with mannitol (A,B). Mannitol treated TgCRND8 mice were notsignificantly different from untreated TgCRND8 mice (p=0.89; A). Theperformance of mannitol treated TgCRND8 mice was significantly differentfrom mannitol treated non-Tg littermates (p=0.05; B). Plaque burden wasanalyzed at 6 months of age using quantitative image analyses (C).Mannitol treated TgCRND8 mice were indistinguishable from untreatedTgCRND8 mice when plaque count was used as a measure of total plaqueburden (p=0.87). Vertical bars represent S.E.M. Kaplan-Meier Cumulativesurvival plots for TgCRND8 mice treated and untreated with mannitol (D).The two cohorts of animals, n=35 per group, were not significantlydifferent as determined by the Tarone-Ware statistical test, p=0.87.

FIGS. 12A and B show the results of a spatial reference memory test inthe treatment studies when performed in a 3-day trial paradigm. Theperformance of scyllo-inositol treated TgCRND8 mice was comparable toscyllo-inositol treated non-Tg littermates (p=0.38; A). In agreement,scyllo-inositol treated TgCRND8 mice remained indistinguishable fromnon-Tg littermates after two months of treatment (p=0.67; B).

FIGS. 13A and B show Aβ levels within the CNS after administration ofvarious doses of scyllo-inositol were administered once daily for onemonth to five month old TgCRND8 mice. Soluble Aβ42 levels were decreasedat all doses and were significantly different from untreated controls(A). In contrast, insoluble Aβ42 was not significantly different underall conditions (B). Vertical bars represent S.E.M.

FIG. 14. TgCRND8 mice administered various doses of scyllo-inositol oncedaily for one month were analyzed for levels of brain Aβ40. Nodifference was detected in soluble (A) and insoluble (B) levels of Aβ40of untreated and scyllo-inositol treated TgCRND8 mice at all dosesexamined.

FIG. 15 shows the cognitive performance of 6-month oldallo-inositol-treated TgCRND8 mice compared with that of theirnon-transgenic littermates.

FIGS. 16A-D show that at 2 months of age, the plaque burden in TgPS1 xAPP mice is decreased in scyllo-inositol treated mice. Control animalshave a high plaque load in the hippocampus (A) and cerebral cortex (B).Scyllo-inositol treatment significantly decreased amyloid burden (C, D).Plaque burden identified using anti-Aβ antibody (brown). Scale Bar 300μm.

FIGS. 17A-C show the quantification of the plaque burden in TgPS1xAPPmice after scyllo-inositol treatment. The percent brain area covered inplaques (A), mean plaque size (B) and plaque count (C) weresignificantly reduced. Vertical bars are S.E.M.

DETAILED DESCRIPTION OF THE INVENTION

The present invention discloses novel, unpredictable and unexpectedproperties of certain inositol stereoisomers in relation to thetreatment of amyloid-related disorders such as Alzheimer's Disease.

It has been surprisingly discovered that certain stereoisomers ofinositol and related compounds block Aβ-induced progressive cognitivedecline and cerebral amyloid plaque pathology, and improve survival whengiven to a transgenic mouse model of human Alzheimer Disease during thenascent phase of Aβ deposition.

As disclosed above, previous data suggested that some, but not all,inositol stereoisomers might have an effect on amyloid aggregation incultured neuronal cells in vitro (McLaurin et al., J. Biol. Chem.275(24): 18495-18502 (2000)). Those observations did not provide anymethod to predict which, if any, of the studied stereoisomers (myo-,epi-, scyllo- and chiro-inositols) would have such effects, nor whetherany other stereoisomers would have such effects. Also, those studiescould not predict if any inositol stereoisomers would have effects onamyloid deposition, cognitive defects or lifespan in vivo. The presentinvention describes the unpredictable results that only certain inositolstereoisomers, in particular scyllo- and allo-inositols reduce amyloidplaque burden, improve cognition and increase lifespan in animal modelsof amyloid-related disorders, whereas others studied did not have sucheffects.

Previous studies also suggested only that certain inositol stereoisomers(e.g. epi- and scyllo-inositols) might inhibit de novo amyloidaggregation in vitro. The present invention describes the unexpectedresults that scyllo-inositol inhibits already established cerebralamyloid deposition, and does so in the living brain. This is not impliedby the previously published in vitro data which considered only certainneuronal cell types in culture, not the complex tissues of the livingbrain, and only suggested that inositols might inhibit de novoaggregation, thereby having no relevance to established disease.

Previous in vitro data also suggested that epi- and scyllo-inositoladministration affects amyloid Aβ40 levels as well as Aβ42 levels. Thein vivo dosing study of the present invention revealed the unpredictableresult that administration of allo- or scyllo-inositol specificallyreduced Aβ42 levels, whereas insoluble Aβ42 and either soluble orinsoluble Aβ40 levels were unaffected.

The observation of the present invention showing changes in glialactivity and inflammation is novel and surprising, and could not havebeen predicted by the in vitro data previously published.

The observation of the present invention demonstrating thatscyllo-inositol improves lifespan in transgenic model animals is alsonovel and surprising, since no drug for Alzheimer's Disease haspreviously been shown to increase survival and extend lifespan in vivo.

Preferably, the compounds of the present invention are1,2,3,4,5,6-cyclohexanehexols, more preferably selected from the groupof cis-, epi-, allo-, muco-, neo-, scyllo-, D-chiro- andL-chiro-inositols.

Also preferably, these compounds are 1,2,3,4,5-cyclohexanepentols(quercitols), more preferably selected from the group of epi-, vibo-,scyllo-, allo-, talo-, gala-, cis-, muco-, neo-, proto-quercitols andenantiomers thereof.

Also preferably, these compounds are selected from the group of acyclohexanetetrol, a cyclohexanetriol, stereoisomer ofcyclohexanetetrol, stereoisimer of cyclohexanetriol, enantiomer ofcyclohexanetetrol, and enantiomer of cyclohexanetriol.

These compounds may also be compound is pentahydxycyclohexanones orstereoisomers or enantiomers thereof.

Yet again preferably, these compounds are inosose compounds selectedfrom the group of scyllo-inosose, L-chiro-inosose-1 and L-epi-inosose.

Also preferably, these compounds are trihydroxyxcyclohexanones, orstereoisomers or enantiomers thereof. More preferably,(−)-1-deoxy-scyllo-inosose.

Also preferably, these compounds are pentahydxycyclohexanones (inosose),or stereoisomers or enantiomers thereof, more preferably selected fromthe group of scyllo-inosose, L-chiro-inosose-1 and L-epi-inosose.

Optionally, these compounds are trihydroxyxcyclohexanones orstereoisomers or enantiomers thereof such as (−)-1-deoxy-scyllo-inosose.

Also preferably, these compounds are O-monomethyl-cyclohexanehexols orstereoisomers or enantiomers thereof, more preferably selected from thegroup of D-pinitol, L-quebrachitol and D-bornesitol.

Again, these compounds may be selected from the group ofmonoaminocyclohexanepentols (inosamines), diaminocyclohexanetetrols(inosadiamines), diaminocyclohexanetriols, stereoisomers thereof, andenantiomers thereof, and pharmaceutically acceptable salts thereof suchas L-neo-inosamine, D,L-epi-inosamine-2, streptamine anddeoxystreptamine.

Yet again preferably, these compounds aremonomercapto-cyclohexanepentols or stereoisomers or enantiomers thereof,more preferably 1L-1-deoxy-1-mercapto-8-O-methyl-chiro-inositol.

The most preferred compounds of the present invention are allo-inositoland scyllo-inositol, with scyllo-inositol being the most preferred. Asindicated above, the inositol stereoisomers of the present inventionexclude myo-inositol and may also exclude epi-inositol.

Even when given after the amyloid pathology has been well establishedfor several months, these compounds effectively reverse cerebral Aβaccumulation and amyloid pathology.

Accordingly, these compounds are found to be useful in treating orpreventing in a subject a condition of the central or peripheral nervoussystem or systemic organ associated with a disorder in protein foldingor aggregation, or amyloid formation, deposition, accumulation, orpersistence. These compounds are also found to be useful in preventingabnormal protein folding, abnormal protein aggregation, amyloidformation, deposition, accumulation, or persistence, or amyloid lipidinteractions as well as causing the dissociation of abnormallyaggregated proteins and/or dissolving or disrupting pre-formed orpre-deposited amyloid fibril or amyloid in a subject.

Preferably, the condition of the central or peripheral nervous system orsystemic organ results in the deposition of proteins, protein fragmentsand peptides in beta-pleated sheats and/or fibrils and/or aggregates.More preferably, the condition of the central or peripheral nervoussystem or systemic organ is selected from the group of: Alzheimer'sdisease, presenile and senile forms; amyloid angiopathy; mild cognitiveimpairment; Alzheimer's disease-related dementia; tauopathy;α-synucleinopathy; Parkinson's disease; Amyotrophic Lateral Sclerosis;motor neuron Disease; Spastic paraplagia; Huntington's Disease,spinocerebellar ataxia, Freidrich's Ataxia; neurodegenerative diseasesassociated with intracellular and/or intraneuronal aggregates ofproteins with polyglutamine, polyalanine or other repeats arising frompathological expansions of tri- or tetra-nucleotide elements withincorresponding genes; cerebrovascular diseases; Down's syndrome; headtrauma with post-traumatic accumulation of amyloid beta peptide; Prionrelated disease; Familial British Dementia; Familial Danish Dementia;Presenile Dementia with Spastic Ataxia; Cerebral Amyloid Angiopathy,British Type; Presenile Dementia With Spastic Ataxia Cerebral AmyloidAngiopathy, Danish Type; Familial encephalopathy with neuroserpininclusion bodies (FENIB); Amyloid Polyneuropathy; Inclusion Bodymyositis due to amyloid beta peptide; Familial and Finnish TypeAmyloidosis; Systemic amyloidosis associated with multiple myeloma;Familial Mediterranean Fever; chronic infections and inflammations; andType II Diabetes Mellitus associate with islet amyloid polypeptide(IAPP).

Also preferably, the Alzheimer's disease-related dementias are vascularor Alzheimer dementia and tauopathy selected from the group ofargyrophilic grain dementia, corticobasal degeneration, dementiapugilistica, diffuse neurofibrillary tangles with calcification,frontotemporal dementia with parkinsonism, Prion-related disease,Hallervorden-Spatz disease, myotonic dystrophy, Niemann-Pick diseasetype C, non-Guamanian Motor Neuron disease with neurofibrillary tangles,Pick's disease, postencephalitic parkinsonism, prion protein cerebralamyloid angiopathy, progressive subcortical gliosis, progressivesupranuclear palsy, subacute sclerosing panencephalitis, and tangle onlydementia.

Also preferably, the α-synucleinopathy is selected from the group ofdementia with Lewy bodies, multiple system atrophy with glialcytoplasmic inclusions, Shy-Drager syndrome, striatonigral degeneration,olivopontocerebellar atrophy, neurodegeneration with brain ironaccumulation type I, olfactory dysfunction, and amyotrophic lateralsclerosis.

Again preferably, the Motor Neuron Disease is associated with filamentsand aggregates of neurofilament and/or superoxide dismutase proteins,the Spastic paraplegia is associated with defective function ofchaperones and/or triple A proteins and the spinocerebellar ataxia isDRPLA or Machado-Joseph Disease.

Also preferably, the Prion related disease is selected from the group ofCreutzfeldt-Jakob disease, Gerstmann-Sträussler-Scheinker disease, andvariant Creutzfeldt-Jakob disease and the Amyloid Polyneuropathy isSenile amyloid polyneuropathy or Systemic Amyloidosis.

More preferably, the condition of the central or peripheral nervoussystem or systemic organ is Parkinson's disease including familial andnon-familial types. Most preferably, said condition of the central orperipheral nervous system or systemic organ is Alzheimer's disease.

Preferably, the compound is administered to the subject at a dose ofabout 1 mg to about 1 g per kg, preferably 1 mg to about 200 mg per kg,more preferably about 10 mg to about 100 mg per kg and most preferablyabout 30 mg to 70 mg per kg of the weight of said subject. Theadministration can be accomplished by a variety of ways such as orally(oral pill, oral liquid or suspension), intravenously, intramuscularly,intraperitoneally, intradermally, transcutaneously, subcutaneously,intranasally, sublingually, by rectal suppository or inhalation, withthe oral administration being the most preferred. The administration ofthe compounds of the present invention can be undertaken at variousintervals such as once a day, twice per day, once per week, once a monthor continuously.

Preferably, the compounds of the present invention are administered incombination with other treatments such as beta-secretase inhibitors,gamma-secretase inhibitors (APP-specific or non-specific),epsilon-secretase inhibitors (APP-specific or non-specific), otherinhibitors of beta-sheet aggregation/fibrillogenesis/ADDL formation(e.g. Alzhemed), NMDA antagonists (e.g. memantine), non-steroidalanti-inflammatory compounds (e.g. Ibuprofen, Celebrex), anti-oxidants(e.g. Vitamin E), hormones (e.g. estrogens), nutrients and foodsupplements (e.g. Gingko biloba); acetylcholinesterase inhibitors,muscarinic agonists (e.g. AF102B (Cevimeline, EVOXAC), AF150(S), andAF267B), anti-psychotics (e.g. haloperidol, clozapine, olanzapine);anti-depressants including tricyclics and serotonin reuptake inhibitors(e.g. Sertraline and Citalopram Hbr), gene therapy and/or drug basedapproaches to upregulate neprilysin (an enzyme which degrades Aβ); genetherapy and/or drug based approaches to upregulate insulin degradingenzyme (an enzyme which degrades Aβ), vaccines, immunotherapeutics andantibodies to Aβ(e.g. ELAN AN-1792), statins and other cholesterollowering drugs (e.g. Lovastatin and Simvastatin), stem cell and othercell-based therapies, inhibitors of kinases (CDK5, GSK3α, GSK3β) thatphosphorylate TAU protein (e.g. Lithium chloride), or inhibitors ofkinases that modulate Aβ production (GSK3α, GSK3β, Rho/ROCK kinases)(e.g. lithium Chloride and Ibuprofen).

It is believed that these other therapies act via a different mechanismand may have additive/synergistic effects with the present invention. Inaddition, many of these other therapies will have mechanism-based and/orother side effects which limit the dose or duration at which they can beadministered alone.

Because of their ability to bind amyloids in vivo as discussedhereinbelow in more detail, the compounds of the present invention arealso useful in diagnosing the presence of abnormally folded oraggregated protein and/or amyloid fibril or amyloid in a subject using amethod that comprises administering to said subject a radioactivecompound or compound tagged with a substance that emits a detectablesignal in a quantity sufficient and under conditions to allow for thebinding of said compound to the abnormally folded or aggregated proteinand/or fibrils or amyloid, if present; and detecting the radioactivityor the signal from the compound bound to the abnormally folded oraggregated protein and/or fibrils or amyloid, thus diagnosing thepresence of abnormally folded or aggregated protein and/or amyloidfibril or amyloid.

Alternatively, a sample suspected of containing abnormally folded oraggregated protein and/or amyloid fibril or amyloid is collected from asubject and is contacted with a radioactive compound or compound taggedwith a substance that emits a detectable signal under conditions toallow the binding of said compound to the abnormally folded oraggregated protein and/or amyloid fibril or amyloid if present; andthereafter detect the radioactivity or the signal from the compoundbound to the abnormally folded or aggregated protein and/or fibrils oramyloid, thus diagnosing the presence of abnormally folded or aggregatedprotein and/or amyloid fibril or amyloid in said subject.

Preferably, said detectable signal is a fluorescent or an enzyme-linkedimmunosorbent assay signal and said sample is whole blood (including allcellular constituents) or plasma.

As shown hereinbelow, the compounds of the present invention canabrogate the cerebral accumulation of Aβ, the deposition of cerebralamyloid plaques, and cognitive decline in a transgenic mouse model ofAlzheimer Disease when given during the “late presymptomatic” phase,prior to the onset of overt cognitive deficits and amyloidneuropathology in these mice. Furthermore, even when these compounds aregiven after the onset of cognitive deficits and amyloid plaqueneuropathology, they can effectively reverse the amyloid deposition andneuropathology. Importantly, the mechanism of action of these compoundsfollows a rational design based upon their capacity to modulate theassembly of Aβ monomers into neurotoxic oligomers and/or protofibrils.

Other advantages of the compounds of the present invention include thefact that they are transported into the CNS by both known transportersand by passive diffusion, and therefore provide ready CNSbioavailablility. Second, these compounds are catabolized to glucose.Third, as a class, these compounds generally have low toxicity profiles,and some of them have previously been given to humans albeit for adifferent purpose.

EXAMPLE 1 Development of Alzheimer's Mouse Model and Methods ofAdministering Compounds of the Present Invention

TgCRND8 mice are a robust murine model of Alzheimer's disease asdescribed by Janus et al. (Nature 408:979-982 (2000). They express ahuman amyloid precursor protein (APP695) transgene under the regulationof the Syrian hamster prion promoter on a C3H/B6 outbred background. Thehuman APP695 transgene bears two mutations that cause AD in humans(K670N/M671L and V717F). Beginning at about 3 months of age, TgCRND8mice have progressive spatial learning deficits that are accompanied byrising cerebral Aβ levels and by increasing number of cerebralextracellular amyloid plaques that are similar to those seen in thebrains of humans with AD (C. Janus et al., Nature 408:979-982 (2000)).

Age and sex-matched cohorts of TgCRND8 mice and non-transgeniclittermates (n=35 in each cohort) were either untreated, or were given acompound of the present invention as indicated below at 30 mg/day/mousebeginning at age of about 6 weeks. The mice were followed for outcomemeasures cognitive function, brain Aβ levels, brain pathology, andsurvival at 4 months and 6 months of age.

Prevention Studies Methods

Mice—Experimental groups of TgCRND8 mice were fed myo-, epi- andscyllo-inositol at 30 mg/mouse/day. Two cohorts entered the study at 6weeks of age and outcomes were analyzed at 4- and 6-months of age. Thebody weight, coat characteristics and in cage behavior was monitored.All experiments were performed according to the Canadian Council onAnimal Care guidelines.

Behavioral tests—After non-spatial pre-training, mice underwent placediscrimination training for 5 days with 4 trials per day. Behavioraldata was analyzed using a mixed model of factorial analysis of variance(ANOVA) with drug or genotype and training sessions as repeated measurefactors.

Cerebral amyloid burden—Brains were removed and one hemisphere was fixedin 4% paraformaldehyde and embedded in paraffin wax in the mid saggitalplane. To generate sets of systematic uniform random sections, 5 μmserial sections were collected across the entire hemisphere. Sets ofsections at 50 mm intervals were used for analyses (10-14 sections/set).Plaque were identified after antigen retrieval with formic acid, andincubated with primary anti-Aβ antibody (Dako M-0872), followed bysecondary antibody (Dako StreptABCcomplex/horseradish kit). End productswere visualized with DAB counter-stained with hematoxylin. Amyloidplaque burden was assessed using Leco IA-3001 image analysis softwareinterfaced with Leica microscope and Hitachi KP-M1U CCD video camera.Vascular burden was analyzed similarly and a dissector was used tomeasure the diameter of affected vessels.

Plasma and Cerebral Aβ Content—Hemi-brain samples were homogenized in abuffered sucrose solution, followed by either 0.4% diethylamine/100 mMNaCl for soluble Aβ levels or cold formic acid for the isolation oftotal Aβ. After neutralization the samples were diluted and analyzed forAβ40 and Aβ42 using commercially available kits (BIOSOURCEInternational). Each hemisphere was analyzed in triplicate with themean±SEM reported. Western blot analyses were performed on all fractionsusing urea gels for Aβ species analyses. Aβ was detected using 6E10(BIOSOURCE International) and Enhanced Chemiluminenscence (Amersham).

Analysis of APP in brain—Mouse hemi-brain samples were homogenized in 20mM Tris pH7.4, 0.25 M sucrose, 1 mM EDTA and 1 mM EGTA, and a proteaseinhibitor cocktail, mixed with 0.4% DEA (diethylamine)/10 mM NaCl andspun at 109,000×g. The supernatants were analysed for APPs levels byWestern blotting using mAb 22C11, while the pellets were analysed forAPP holoprotein using mAb C1/6.1.

Gliosis Quantitation—Five randomly selected, evenly spaced, sagittalsections were collected from paraformaldehyde-fixed and frozenhemispheres of treated and control mice. Sections were immunolabelledfor astrocytes with anti-rat GFAP IgG_(2a) (Dako; diluted 1:50) and formicroglia with anti-rat CD68 IgG2b (Dako; 1:50). Digital images werecaptured using a Coolsnap digital camera (Photometrics, Tuscon, Ariz.)mounted to a Zeiss Axioscope 2 Plus microscope. Images were analysedusing Openlab 3.08 imaging software (Inprovision, Lexington Mass.).

Survival Census—The probability of survival was assessed by theKaplan-Meier technique, computing the probability of survival at everyoccurrence of death, thus making it suitable for small sample sizes. Forthe analyses of survival, 35 mice were used for each treatment group.The comparison between treatments was reported using the Tarone-Waretest.

EXAMPLE 2 Prevention of Cognitive Deficits

The cognitive function of TgCRND8 mice was assessed using the spatialreference memory version of the Morris Water Maze using a five-day trialparadigm (FIGS. 1C-1H). Data from treated and non-treated TgCRND8 mice,and from treated and non-treated non-Tg littermates (n=10 for allcombinations) were analyzed using a mixed model of analysis of variance(ANOVA) with treatment (untreated, epi- or scyllo-inositol) and genotype(TgCRND8 versus non-Tg) as ‘between-subject’ factors. TgCRND8 micetreated with either epi- or scyllo-inositol performed significantlybetter than untreated TgCRND8 mice (p<0.02; FIGS. 1C and D). Whencompared to treated or non-treated non-Tg littermates, epi-inositoltreated TgCRND8 mice had a slightly slower learning curve during thefirst three days of training. However, after 4 days of training,epi-inositol treated TgCRND8 mice were not statistically different fromtheir non-Tg littermates (FIG. 2E). In contrast, scyllo-inositol treatedTgCRND8 mice were indistinguishable from non-Tg littermates on all days.Thus both stereoisomers inhibited the development of cognitive deficits,and scyllo-inositol actually prevented the deficits to such a degreethat the scyllo-inositol treated TgCRND8 mice were indistinguishablefrom normal mice. This improved performance was not due to anon-specific effect on behavioral, motoric, or perceptual systemsbecause epi- and scyllo-inositol treatment had no effect on theperformance of non-Tg mice (FIGS. 2G and 2H). The improved performancewas also not due to nutritional or caloric effects because body weight,activity, and coat condition were not different between treated anduntreated cohorts. Furthermore, treatment with mannitol (a sugar ofsimilar molecular weight) had no effect on behavior. Gender effects werenot significant between any treatment group (p=0.85).

EXAMPLE 3 Reduction of Cerebral Aβ Burden and Amyloid Neuropathology

At four months of age, untreated TgCRND8 mice have a robust expressionof both Aβ40 and Aβ42 (Table 1). Epi-inositol treatment as described inExample 1 reduced both Aβ 40 (43±2% reduction in both soluble andinsoluble pools; p<0.05) and Aβ 42 levels (69% reduction in solublepool, p=0.005; 28% reduction in insoluble pool, p=0.02) at 4-months ofage. However, these improvements were not sustained, and by 6 months ofage, brain Aβ levels rose to levels similar to those observed inuntreated TgCRND8 mice (Table 1).

In contrast, at four months of age, scyllo-inositol treatment decreasedtotal brain Aβ40 by 62% (p=0.0002) and total brain Aβ42 by 22%(p=0.0096; Table 1). At 6 months of age, scyllo-inositol treatmentcaused a 32% reduction in Aβ40 levels (p=0.04) and 20% reduction in Aβ42(p=0.02) compared to untreated TgCRND8 mice.

Because the decreased Aβ concentrations detected after inositoltreatment could have resulted from altered efflux of Aβ into the plasma,Aβ-β levels in the plasma were examined at 4- and 6-months of age (Table1). TgCRND8 mice have high plasma Aβ concentrations at 4-months of ageand remain constant at 6 months of age even though CNS plaque load isstill rising at 6-months of age (Table 1). Neither epi-inositol norscyllo-inositol treatment had any effect on plasma Aβ levels incomparison to untreated TgCRND8 mice (p=0.89). The most parsimoniousexplanation for this observation is that the inositols have selectivelyaltered the fibrillization of Aβ in the CNS, but have not affected β- orγ-secretase activity, or the normal mechanisms for clearance of Aβ intoplasma. Nevertheless, this observation is significant for two reasons.First, a drop in plasma and CSF Aβ levels is usually detected as theclinical course progresses in untreated AD patients (Mayeux, et al.,Ann. Neurol 46, 412, 2001). Secondly, patients in the AN1792immunization study who developed a strong antibody response and anapparent clinical response did not have altered plasma Aβ-β levels (Hocket al., Neuron 38, 547 2003). Therefore, these results indicate that itis not necessary to change plasma Aβ levels to obtain an effectivetherapeutic outcome.

To confirm that inositol stereoisomers had no effect on either theexpression or proteolytic processing of APP, the levels of APPholo-protein, sAPP-α, and various Aβ species were examined within thebrain of inositol-treated and untreated TgCRND8 mice. Consistent withour previously reported data (McLaurin, et al., Nat. Med. 8, 1263,2002), Aβ42, Aβ40 and Aβ38 are the predominant species in the brain ofTgCRND8 mice (FIG. 3A), and the CNS levels of immature and matureglycolyslated APP (FIG. 3B), and of sAPP-α were indistinguishableregardless of treatment. In combination, these results indicate thatepi- and scyllo-inositol have a direct and selective effect on Aβoligomerization and not the processing of APP.

The changes in Aβ-β peptide load were accompanied by a significantdecrease in plaque burden (Table 1; FIGS. 2A-2I). In epi-inositoltreated TgCRND8 mice, there was a significant decrease in the meanplaque size at 4- but not 6-months of age compared with untreatedTgCRND8 mice (95±4.3 μm² versus 136±15 μm², p=0.04; 370±9 μm² versus423±22 m², p=0.06, respectively). These results indicate that at modestAβ levels, epi-inositol prevents Aβ oligomerization but once initiatedat higher Aβ concentrations, epi-inositol is unable to inhibitfibrillogenesis. Scyllo-inositol treatment decreased the mean plaquesize from 136±151 m² to 103±4 μm² (p=0.01) at 4 months of age. Inscyllo-inositol treated TgCRND8 mice at 6 months of age, the decrease inAβ peptide levels was accompanied by a 20% reduction in plaque number(p=0.005), a 35% decrease in brain area covered with plaques (p=0.015)and a decreased mean plaque size (339±10 vs. 423±21 μm², p=0.009). Theseresults demonstrate that by every measure there was a reduction inplaque burden after scyllo-inositol treatment.

TABLE 1 Inositol treatment decreases Aβ40 and Aβ42 Levels Aβ40 Aβ42Total Plaque (ng/gm wet (ng/gm wet Plaque Area/Total brain ± sem) brain± sem) Total Plaque Area Brain Area Soluble Insoluble Soluble InsolubleAβ Count (μm²) (%) 4 month prevention Control 75 ± 6 1163 ± 9   273 ± 185658 ± 248  7169 ± 284 696 ± 25 100766 ± 7564  0.026 ± 0.004Epi-Inositol  43 ± 7* 615 ± 32†  85 ± 7† 4059 ± 179* 4802 ± 176 678 ± 6465042 ± 5199 0.020 ± 0.001 Scyllo-Inositol  37 ± 5* 437 ± 80† 206 ± 8*4409 ± 135* 5089 ± 173  598 ± 19* 63847 ± 2895  0.015 ± 0.001* 6 monthprevention Control 187 ± 29 3576 ± 172  626 ± 87 15802 ± 237  20191 ±211  960 ± 44 411288 ± 11912 0.120 ± 0.001 Epi-Inositol 188 ± 24 3668 ±149  665 ± 39 13943 ± 277†  18464 ± 229  979 ± 32 380456 ± 13498 0.096 ±0.04  Scyllo-Inositol 105 ± 8*  2453 ± 251*†  475 ± 26* 12588 ± 82† 15621 ± 151   774 ± 10*† 262379 ± 5373†  0.079 ± 0.013† Plasma Aβ Levels(pg/ml) 4 month prevention 6 month prevention Control 1018 ± 27  915 ±59 Epi-Inositol 1082 ± 164 952 ± 56 Scyllo-Inositol 952 ± 49 905 ± 55Anova with Fisher's PLSD, †p < 0.001 and *p < 0.05

EXAMPLE 4 Reduction of Glial Reactivity and Inflammation

Astroglial and microglial reactions are neuropathological features bothof human AD and of all amyloid mouse models (Irizarry et al., JNeuropathol Exp Neurol. 56, 965, 1997; K. D. Bornemann et al. Ann NYAcad Sci. 908, 260, 2000). Therefore, the effect of epi- andscyllo-inositol treatment was investigated on astrogliosis andmicrogliosis in the brains of TgCRND8 mice (FIGS. 3A-3D). Serialsagittal sections were stained with the astrocytic marker glialfibrillary acidic protein (GFAP) and quantitated for percent brain areacovered by astrogliosis. TgCRND8 mice have a high basal astrogliosis at4-months of age (0.459±0.048%), which increases slightly by 6-months ofage (0.584±0.089%), and which is not restricted to plaque areas (FIGS.2A-C). Epi-inositol decreased the astrogliotic response to 0.388±0.039%at 6-months of age (p=0.04; FIG. 2D-F). Scyllo-inositol, on the otherhand, decreased astrogliosis much more efficiently to 0.269±0.028% at6-months of age, (p=0.006)(FIG. 2G-I). Microglial activation was alsosignificantly attenuated in scyllo-inositol treated TgCRND8 mice(0.20±0.008% brain area) when compared to age- and sex-matched untreatedTgCRND8 mice (0.31±0.01%; p<0.001). However, epi-inositol treated micedemonstrated no significant reduction in microglial activation at 6months (0.248±0.02%; p=NS). Taken together these data indicate thatscyllo-inositol treatment decreases the Aβ-induced inflammatory responsewithin the CNS.

EXAMPLE 5 Reduction of Vascular Amyloid Load

Alzheimer's disease is characterized by the presence of both parenchymaland vascular amyloid deposits. In untreated 6 month old TgCRND8 miceapproximately 0.03% of the brain area is associated with vascularamyloid. No difference could be detected in the vascular amyloid burdenafter epi-inositol treatment at 6 months of age (FIG. 3C). In contrast,scyllo-inositol treatment significantly decreased the vascular amyloidburden (p—0.05) (FIG. 3C), and the amyloid deposition was predominantlylocalized to smaller vessels, <25 m² in diameter (56±2% versus 70±8% insmall vessels in untreated TgCRND8 mice). The mean size ofcerebrovascular plaques was significantly decreased in thescyllo-inositol treated mice in comparison to untreated mice (154±16 vs.363±34, p=0.008; FIG. 3D).

EXAMPLE 6 Survival Improvement

TgCRND8 mice have a 50% survival at 175 days, which after treatment wasimproved to 72% with scyllo-inositol (n=35 per group, p<0.02 forscyllo-inositol vs. control, FIG. 10B). Treatment with myo-inositol didnot affect overall survival significantly (FIG. 10A). Controlexperiments confirmed that the enhanced survival of scyllo-inositoltreated mice was not an indirect effect of increased caloric intake.Thus, treatment of wild type mice with scyllo-inositol had no effecteither on survival or on other parameters such as weight, fur conditionor cage behavior. Furthermore, the weight, fur condition and home-cagebehavior of the inositol-treated TgCRND8 mice did not vary fromuntreated TgCRND8 mice. Simultaneous experiments with mannitol, a simplesugar of similar molecular weight, also had no effect on survival ofTgCRND8 mice.

EXAMPLE 7 Treatment and Reversal of Amyloid Deposition

Taken together, the prevention studies demonstrate that scyllo-inositolinhibits both parenchymal and cerebrovascular amyloid deposition andresults in improved survival and cognitive function in the TgCRND8 mousemodel of Alzheimer disease. However, most Alzheimer's disease patientswill likely seek treatment only once symptomatic, and when Aβoligomerization, deposition, toxicity and plaque formation are alreadywell advanced within the CNS. A pilot study was therefore initiated on 5month old TgCRND8 mice. These mice have significant Aβ and plaqueburdens that are comparable to those in the brain of humans with AD.

Treatment Study Methods

Mice—Experimental groups of TgCRND8 mice were fed myo-, epi- andscyllo-inositol at 30 mg/mouse/day. A cohort entered the study at 5months of age and outcomes were analyzed at 6-months of age. The bodyweight, coat characteristics and in cage behavior was monitored. Allexperiments were performed according to the Canadian Council on AnimalCare guidelines.

Survival Census—The probability of survival was assessed by theKaplan-Meier technique, computing the probability of survival at everyoccurrence of death, thus making it suitable for small sample sizes. Forthe analyses of survival, 35 mice were used for each treatment group.The comparison between treatments was reported using the Tarone-Waretest.

Behavioral Test—Reversal Study—Mice entered the Morris water maze testwith a hidden platform on day one without pretraining. Mice were testedfor 3 days with six trials per day. On the fourth day, the platform wasremoved from the pool and each mouse received one 30-s swim probe trial.On the last day the animals underwent a cue test in order to evaluateswimming ability, eye sight and general cognition. The cue test iscomposed at the platform being placed in a different quadrant than thatused for testing and is tagged with a flag. Animals are allowed 60 s tofind the platform. Animals that do not find the platform are not used inthe final analyses of spatial memory. Behavioural data was analysedusing a mixed model of factorial analysis of variance (ANOVA) with drugor genotype and training sessions as repeated measure factors.

Cerebral amyloid burden—Brains were removed and one hemisphere was fixedin 4% paraformaldehyde and embedded in paraffin wax in the mid saggitalplane. To generate sets of systematic uniform random sections, 5 μmserial sections were collected across the entire hemisphere. Sets ofsections at 50 mm intervals were used for analyses (10-14 sections/set).Plaque were identified after antigen retrieval with formic acid, andincubated with primary anti-Aβ antibody (Dako M-0872), followed bysecondary antibody (Dako StreptABCcomplex/horseradish kit). End productswere visualized with DAB counter-stained with hematoxylin. Amyloidplaque burden was assessed using Leco IA-3001 image analysis softwareinterfaced with Leica microscope and Hitachi KP-M1U CCD video camera.

Plasma and Cerebral Aβ Content—Hemi-brain samples were homogenized in abuffered sucrose solution, followed by either 0.4% diethylamine/100 mMNaCl for soluble Aβ levels or cold formic acid for the isolation oftotal Aβ. After neutralization the samples were diluted and analyzed forAβ40 and Aβ42 using commercially available kits (BIOSOURCEInternational). Each hemisphere was analyzed in triplicate with themean±SEM reported.

Results and Significance−All animals that entered the reversal studysurvived and did not display outward signs of distress or toxicity. Thecognitive function of TgCRND8 mice was assessed using the spatialreference memory version of the Morris Water Maze using a three daytrial paradigm (FIGS. 4-8). Data from treated and non-treated TgCRND8mice, and from treated and non-treated non-Tg littermates (n=10 for allcombinations) were analyzed using a mixed model of analysis of variance(ANOVA) with treatment (untreated, myo-, epi- or scyllo-inositol) andgenotype (TgCRND8 versus non-Tg) as ‘between-subject’ factors. In thisparadigm TgCRND8 mice were significantly impaired in comparison to wildtype littermates (FIG. 4). In contrast, scyllo-inositol treated TgCRND8mice were indistinguishable from non-Tg littermates on all days.(p=0.38; FIG. 5). When compared to treated non-Tg littermates,epi-inositol treated TgCRND8 mice were almost significantly different(p=0.07; FIG. 6). Similarly, myo-inositol treated TgCRND8 mice weresignificantly different from treated non-Tg littermates (p=0.05, FIG.7). When the learning phase of the Morris water maze test is comparedbetween treatments, all mice behaved similarly (FIG. 8). In contrast,only scyllo-inositol was indistinguishable from non-Tg littermates (FIG.8). Thus, scyllo-inositol actually reversed the cognitive deficits tosuch a degree that the scyllo-inositol treated TgCRND8 mice wereindistinguishable from normal mice. This improved performance was notdue to a non-specific effect on behavioral, motoric, or perceptualsystems because epi- and scyllo-inositol treatment had no effect on theperformance of non-Tg mice. The improved performance was also not due tonutritional or caloric effects because body weight, activity, and coatcondition were not different between treated and untreated cohorts.

In order to determine if the improved cognition was associated withdecreased plaque burden and Aβ load, brain tissue was examinedpost-mortem. The changes in cognition were accompanied by acorresponding change in plaque burden and Aβ load (FIG. 9 and Table 2).Myo-inositol treatment did not affect the plaque burden or Aβ load (FIG.9 and Table 2). In epi-inositol treated TgCRND8 mice, there was not asignificant decrease in the mean plaque size compared with untreatedTgCRND8 mice (FIG. 9), yet the Aβ load was significantly decreased(Table 2). These results suggest that at modest Aβ levels, epi-inositolprevents Aβ oligomerization but at higher Aβ concentrations,epi-inositol is unable to inhibit fibrillogenesis completely.Scyllo-inositol treatment significantly decreased the plaque burden andthe Aβ load. These results demonstrate that by every measure there was areduction in plaque burden after scyllo-inositol treatment. Theseresults are comparable in effect size to the 6-month prophylacticstudies, and further support the potential for scyllo-inositol.

Because the decreased Aβ concentrations detected after inositoltreatment could have resulted from altered efflux of Aβ into the plasma,we examined Aβ levels in the plasma (Table 2). TgCRND8 mice have highplasma Aβ concentrations at 6 months of age. Neither myo-inositol,epi-inositol nor scyllo-inositol treatment had any effect on plasma Aβlevels in comparison to untreated TgCRND8 mice (p=0.89). The mostparsimonious explanation for this observation is that the inositols haveselectively altered the fibrillization of Aβ in the CNS, but have notaffected β- or γ-secretase activity, or the normal mechanisms forclearance of Aβ into plasma. Nevertheless, this observation issignificant for two reasons. First, a drop in plasma and CSF Aβ levelsis usually detected as the clinical course progresses in untreated ADpatients. Secondly, patients in the AN1792 immunization study whodeveloped a strong antibody response and an apparent clinical responsedid not have altered plasma Aβ levels. Therefore, these results furtherindicate that it is not necessary to change plasma Aβ levels to obtainan effective therapeutic outcome.

Taken together, these data reveal that selected scyllo-inositol canabrogate the cerebral accumulation of Aβ, the deposition of cerebralamyloid plaques, and cognitive decline in a transgenic mouse model ofAlzheimer Disease when given during the “late presymptomatic” phase,prior to the onset of overt cognitive deficits and amyloidneuropathology in these mice. Furthermore, even when scyllo-inositol isgiven after the onset of cognitive deficits and amyloid plaqueneuropathology, these compounds can effectively reverse the amyloiddeposition, neuropathology and cognitive deficits. Therefore, theseresults indicate that scyllo-inositol is effective at both prevention ofdisease and in the treatment of existing disease in patients alreadydiagnosed with AD.

TABLE 2 Inositol treatment decreases Aβ40 and Aβ42 Levels Aβ40 Aβ42(ng/gm wet (ng/gm wet Plaque Total Plaque brain ± sem) brain ± sem)Total Plaque Area Area/Total Brain Soluble Insoluble Soluble InsolubleAβ Count (μm²) Area (%) 4 month prevention Control 75 ± 6 1163 ± 9  273± 18 5658 ± 248 7169 ± 284 696 ± 25 100766 ± 7564  0.026 ± 0.004Myo-Inositol 42 ± 6  485 ± 143 174 ± 9  4268 ± 308 4969 ± 434 649 ± 5091902 ± 7453 0.023 ± 0.004 Epi-Inositol  43 ± 7*  615 ± 32†  85 ± 7† 4059 ± 179* 4802 ± 176 678 ± 64 65042 ± 5199 0.020 ± 0.001 Scyllo-  37± 5*  437 ± 80† 206 ± 8*  4409 ± 135* 5089 ± 173  598 ± 19* 63847 ± 2895 0.015 ± 0.001* Inositol 6 month prevention Control 187 ± 29 3576 ± 172626 ± 87 15802 ± 237  20191 ± 211 960 ± 44 411288 ± 11912 0.120 ± 0.001Myo-Inositol 221 ± 19 3436 ± 189 543 ± 71 13289 ± 535  17489 ± 354 927 ±78 400013 ± 19638 0.100 ± 0.005 Epi-Inositol 188 ± 24 3668 ± 149 665 ±39 13943 ± 277† 18464 ± 229 979 ± 32 380456 ± 13498 0.096 ± 0.04 Scyllo- 105 ± 8*  2453 ± 251*†  475 ± 26* 12588 ± 82†  15621 ± 151  774± 10*† 262379 ± 5373†  0.079 ± 0.013† Inositol 1 month treatment Control207 ± 16 4965 ± 457 426 ± 14 14503 ± 1071 20101 ± 854 1441 ± 29  486002± 16156 0.159 ± 0.014 Myo-Inositol 194 ± 12 4187 ± 226 487 ± 25 15622 ±675  20490 ± 526 1324 ± 69  469968 ± 35664 0.153 ± 0.088 Epi-Inositol264 ± 11 3637 ± 113 540 ± 14 12830 ± 330  17271 ± 415 1342 ± 114 459706± 49966 0.134 ± 0.017 Scyllo- 178 ± 11 3527 ± 241 374 ± 23 11115 ± 647 15194 ± 579 1260 ± 27*  420027 ± 14986*  0.119 ± 0.010* Inositol PlasmaAβ Levels (pg/ml) 4 month prevention 6 month prevention 1 monthtreatment Control 1018 ± 27  915 ± 59 2287 ± 151 Myo-Inositol 942 ± 30969 ± 67 2110 ± 174 Epi-Inositol 1082 ± 164 952 ± 56 2158 ± 157 Scyllo-952 ± 49 905 ± 55 1980 ± 146 Inositol Anova with Fisher's PLSD, †p <0.001 and *p < 0.05; IP = in progress.

EXAMPLE 8 Two-month Treatment Study with Scyllo-inositol

In order to determine longer efficacy ranges of scyllo-inositol for thetreatment of disease, 5-month old TgCRND8 mice were fed scyllo-inositolor untreated for two months (n=10 per group). The cognitive function of7-month old TgCRND8 mice treated with scyllo-inositol was compared tountreated TgCRND8 and treated non-Tg littermates in the three-dayparadigm of the Morris Water Maze. Behavioural data was analysed using amixed model of factorial analysis of variance (ANOVA) with drug andgenotype as between subject variables and training sessions as withinsubject variable. As was seen with the 1-month treatment ofscyllo-inositol (FIG. 12A), TgCRND8 mice treated for two months withscyllo-inositol were indistinguishable from scyllo-inositol treatednon-Tg littermates (FIG. 12B). In order to correlate the improvedcognition with pathology, Aβ40 and Aβ42 levels were analysed in thebrain (Table 3). Both insoluble Aβ40 and Aβ42 levels were decreased 20%after scyllo-inositol treatment. These results demonstrate thatscyllo-inositol effects persist during disease progression.

TABLE 3 Inositol treatment decreases Aβ40 and Aβ42 Levels Brain Aβ40Brain Aβ42 Plasma (ng/gm wet (ng/gm wet Aβ Levels brain ± sem) brain ±sem) (pg/ml) 2 month treatment Soluble Insoluble Soluble Insoluble Aβ40Aβ42 Control 487 ± 14 6924 ± 287  764 ± 51 25827 ± 1238  5212 ± 219 3455± 331 Scyllo-inositol 395 ± 60 5703 ± 612* 688 ± 28 20818 ± 1404* 4507 ±207 3035 ± 236 ANOVA with Fisher's PLSD, *p < 0.05.

EXAMPLE 9 Effect of Dose on Pathological Outcome in Disease BearingTgCRND8 Mice

5-month old TgCRND8 mice were gavaged once daily with scyllo-inositol inwater at doses of 10 mg/Kg, 30 mg/Kg, 100 mg/Kg or untreated. Animalswere sacrificed after one month of treatment and analysed forpathological outcomes. Analysis of the levels of Aβ within the brain ofall the cohorts demonstrates that all drug doses were effective to thesame extent on lowering soluble Aβ42 levels in comparison to untreatedTgCRND8 mice (20% reduction, F_(3,15)=3.1, p=0.07; FIG. 13A). Analysesof individual doses demonstrate that 10 mg/Kg and 30 mg/Kg doses weresignificantly different from untreated controls (p=0.03 and p=0.02,respectively). None of the doses chosen were significantly differentfrom each other (F_(2,11)=0.6, p=0.57; FIG. 13A). Gavage dosing had nosignificant effect on insoluble Aβ42 (F_(3,15)=0.69, p=0.58; FIG. 13B)or soluble and insoluble Aβ40 (F_(3,5)=0.04, p—0.99 and F_(3,15)=0.36,p=0.79, respectively; FIGS. 14A and 14B).

EXAMPLE 10 Efficacy of Allo-inositol for the Treatment of DiseaseBearing TgCRND8 Mice

To assess whether allo-inositol might also be effective in preventingfurther progression and/or might partially reverse a well-establishedAD-like phenotype, the start of treatment of the TgCRND8 mice wasdelayed until 5 months of age. Cohorts of TgCRND8 and non-transgeniclittermates were either treated for 28 days with allo-inositol, or wereuntreated. In these experiments, the dosage and oral administration ofcompounds, and the behavioral and neurochemical assays were the same asthose employed in the above treatment experiments.

The cohort of 6-month old allo-inositol-treated TgCRND8 mice performedsignificantly better than untreated TgCRND8 mice (F_(1,13)=0.45, p=0.05;data not shown). The cognitive performance of 6-month oldallo-inositol-treated TgCRND8 mice was still significantly differentfrom that of their non-transgenic littermates (F_(1,13)=5.9, p=0.05;FIG. 15). The beneficial effect of inositol treatment was not due tonon-specific effects on behavioral, motor, or perceptual systems becauseinositol treatment had no effect on the cognitive performance of non-Tgmice (F_(1,12)2=0.98; p=0.49). Cerebral Aβ levels were analyzed fortreatment versus untreated TgCRND8 mice to determine whether improvedbehavior could be correlated with changes in Aβ (Table 4). Allo-inositoltreatment reduced soluble Aβ42 (20% reduction, p<0.05) an effect similarto that seen for scyllo-inositol. Allo-inositol did not significantlyalter insoluble Aβ42 or Aβ40 (soluble and insoluble pools). One possibleexplanation for the decrease in Aβ42 is clearance of Aβ42 in theperiphery with a subsequent increase in plasma Aβ42. The levels of Aβ42in plasma after allo-inositol treatment were indistinguishable fromuntreated TgCRND8 plasma levels (Table 5). In agreement with the otherinositol stereoisomers, these results demonstrate that plasma Aβ levelsare unaffected by allo-inositol treatment.

TABLE 4 Allo-Inositol treatment decreases Aβ42 levels Brain Aβ40 BrainAβ42 (ng/gm wet (ng/gm wet Plasma Aβ brain ± sem) brain ± sem) Levels 1month treatment Soluble Insoluble Soluble Insoluble (pg/ml) Control 252± 48 4105 ± 851 666 ± 39  16448 ± 2120 2359 ± 147 Allo-inositol 281 ± 213787 ± 342 547 ± 47* 16336 ± 910  2458 ± 95  ANOVA with Fisher's PLSD,*p < 0.05.

TABLE 5 Blood Biochemistry - scyllo-inositol Dose Study Untreated 100mg/Kg 30 mg/Kg 10 mg/Kg Reference Levels Biochemistry n = 4 n = 4 n = 3n = 5 (Vita-Tech & CCAC) Total protein 46 ± 2 g/L 49 ± 2   50 ± 2.6 50 ±3  35-72 Albumin 35 ± 0 g/L 31 ± 1 33 ± 2 33 ± 4  25-48 Globulin 12 ± 1g/L 19 ± 2 17 ± 1 17 ± 2  18-82 Bilirubin 2.4 ± 1 umol/L 1.9 ± 0  2.0 ±1  1.9 ± 0.6  2-15 ALP 81 ± 10 U/L  76 ± 11  81 ± 10 73 ± 22 28-94 ALT42 ± 4 U/L 38 ± 4 42 ± 4 51 ± 20  28-184 Glucose 11 ± 2 mmol/L 11 ± 2 12± 2 7 ± 2  9.7-18.6 Urea 9 ± 3 mmol/L 7.4 ± 1   9 ± 3 10 ± 2  12.1-20.6Creatinine 36 ± 5 umol/L 31 ± 4 35 ± 5 40 ± 5  26-88 Hemolysis NormalNormal Normal Normal Icteria Normal Normal Normal Normal Lipemia NormalNormal Normal Normal

EXAMPLE 11 Inositol Treatment does not Affect Blood Chemistry

In order to rule out any deleterious effects of inositol treatment onblood chemistry and organ function, blood was analyzed after one monthtreatment with both scyllo- and allo-inositol (Table 5, 6). The totalprotein, albumin, globulin, bilirubin, alkaline phosphatase, glucose,urea and creatinine were not significantly different between treatmentgroups or from untreated TgCRND8 mice. All levels fell within the normalrange as determined for non-transgenic wild type mice. In additionhemolysis, icteria and lipemia were all normal. These results suggestthat allo- and scyllo-inositol do not exhibit obvious deleteriouseffects on blood chemistry or organ function.

TABLE 6 Blood Biochemistry - 1 Month Treatment Study UntreatedAllo-Inositol Reference Levels Biochemistry n = 4 n = 4 (Vita-Tech &CCAC) Total protein 46 ± 2 g/L 48 ± 2 35-72 Albumin 35 ± 0 g/L 32 ± 225-48 Globulin 12 ± 1 g/L 17 ± 3 18-82 Bilirubin 2.4 ± 1 umol/L 2.9 ± 3  2-15 ALP 81 ± 10 U/L  95 ± 16 28-94 ALT 42 ± 4 U/L 44 ± 4  28-184Glucose 11 ± 2 mmol/L 10 ± 3  9.7-18.6 Urea 9 ± 3 mmol/L 18.6 ± 13 12.1-20.6 Creatinine 36 ± 5 umol/L  69 ± 64 26-88 Hemolysis NormalNormal Icteria Normal Normal Lipemia Normal Normal

EXAMPLE 12 Efficacy of Scyllo-inositol in Preventing AD-like Pathologyin a Double Transgenic Mouse Model of Alzheimer's Disease, PS1 x APP

Tg PS1 x APP mice are an enhanced model of Alzheimer's disease whichexpress a mutant human PS1 transgene encoding two familial mutations(M146L and L286V) in conjunction with the human APP transgene encodingthe Indiana and Swedish familial mutations. These animals develop robustexpression of cerebral Aβ levels and amyloid deposition by 30-45 days ofage. In a prophylactic trial, TgPS1xAPP mice were treated withscyllo-inositol from weaning and were assessed for effects onneuropathology at 2 months of age (FIGS. 16 and 17). Compared withuntreated TgPS1xAPP mice, scyllo-inositol treated TgPS1xAPP micedisplayed a significant decrease in all measures of plaque burden at 2months of age (% brain area covered in plaques=0.157±0.007 vs0.065±0.016, p<0.001; mean plaque size=177±8 μm² vs 149±5 μm², p<0.05;plaque count 3054±324 vs 1514±510, p<0.01; (FIG. 17). These resultsdemonstrate that scyllo-inositol prevents amyloid deposition in tworobust models of Alzheimer's disease.

EXAMPLE 13 Effect of Increased Caloric Intake on TgCRND8 Mice

In order to rule out the contribution of increased caloric intake ornon-specific effects, TgCRND8 mice were treated with a simple sugar ofsimilar molecular weight, mannitol. At 6 months of age, mannitol treatedTgCRND8 mice were indistinguishable from untreated TgCRND8 mice (FIG.11A) and were significantly different from mannitol treated non-Tglittermates (FIG. 11B). Mannitol had no effect on the behaviour ofnon-Tg mice, since mannitol treated non-Tg mice were indistinguishablefrom untreated non-Tg mice. These results correlate with thepathological studies that indicate mannitol did not alter the plaqueload in TgCRND8 mice (FIG. 11C). Simultaneous monitoring of survivaldemonstrated that mannitol had no effect on the survival of TgCRND8 mice(FIG. 11D).

Although the present invention has been described in relation toparticular embodiments thereof, many other variations and modificationsand other uses will become apparent to those skilled in the art. Thepresent invention therefore is not limited by the specific disclosureherein, but only by the appended claims.

What is claimed is:
 1. A method of treating Alzheimer's diseasecomprising administering to a patient in need of such treatment anamount of scyllo-inositol of about 1 to about 70 mg/kg/day.
 2. A methodof claim 1 wherein said amount is about 1 to about 10 mg/kg/day.
 3. Amethod of claim 2 wherein said amount dissociates abnormally aggregatedproteins and/or dissolves or disrupts pre-formed or pre-depositedamyloid fibrils or amyloid.
 4. A method of one of claims 1 or 2 whereinthe administration is orally.
 5. A method of claim 4 wherein theadministration is once or twice a day.
 6. A method of claim 2 comprisingadministering scyllo-inositol in a pharmaceutical composition.
 7. Amethod of claim 2 for improving cognition, in an Alzheimer's diseasepatient.
 8. A method of claim 2 for treating a patient in a latepre-symptomatic phase of Alzheimer's disease.
 9. A method of claim 2 forreducing one or more of amyloid plaque burden, amyloid accumulation orAβ42 levels in a patient suffering from Alzheimer's disease.
 10. Amethod of claim 2 wherein scyllo-inositol is administered in an oralpill, liquid or suspension.
 11. A method of claim 2 wherein theAlzheimer's disease is a presenile form.
 12. A method of treating mildcognitive impairment comprising administering to a patient in need ofsuch treatment an amount of scyllo-inositol of about 1 to about 70mg/kg/day.
 13. A method of claim 12 wherein said amount is about 1 toabout 10 mg/kg/day.
 14. A method of claim 13 wherein said amountdissociates abnormally aggregated proteins and/or dissolves or disruptspre-formed or pre-deposited amyloid fibrils or amyloid.
 15. A method ofone of claims 12 or 13 wherein the administration is orally.
 16. Amethod of claim 15 wherein the administration is once or twice a day.17. A method of claim 13 comprising administering scyllo-inositol in apharmaceutical composition.
 18. A method of claim 13 for improvingcognition.
 19. A method of claims 1 or 12 further comprisingadministering an effective amount of an acetyl cholinesterase inhibitor.20. A method of claim 1 or 12 wherein the amount of scyllo-inositol isabout 10 mg/kg/day.
 21. A method of claim 19, wherein the amount ofscyllo-inositol is about 1 to about 10 mg/kg/day.
 22. A method of claim21, wherein the acetylcholinesterase inhibitor is donepezil.
 23. Amethod of claim 21, wherein scyllo-inositol is orally administered. 24.A method of claim 21 comprising administering a combination ofscyllo-inositol and the acetylcholinesterase inhibitor.
 25. A method ofclaim 21, wherein scyllo-inositol is administered once a day.
 26. Amethod of claim 21, wherein scyllo-inositol is administered twice a day.27. A method of claim 21, wherein both scyllo-inositol and theacetylcholinesterase inhibitor are administered orally.
 28. A method ofclaim 21 wherein Alzheimer's disease is treated and is a presenile form.